Schizophrenia in the genetic era: a review from development history, clinical features and genomic research approaches to insights of susceptibility genes.

Schizophrenia is a devastating neuropsychiatric disorder affecting 1% of the world population and ranks as one of the disorders providing the most severe burden for society. Schizophrenia etiology remains obscure involving multi-risk factors, such as genetic, environmental, nutritional, and developmental factors. Complex interactions of genetic and environmental factors have been implicated in the etiology of schizophrenia. This review provides an overview of the historical origins, pathophysiological mechanisms, diagnosis, clinical symptoms and corresponding treatment of schizophrenia. In addition, as schizophrenia is a polygenic, genetic disorder caused by the combined action of multiple micro-effective genes, we further detail several approaches, such as candidate gene association study (CGAS) and genome-wide association study (GWAS), which are commonly used in schizophrenia genomics studies. A number of GWASs about schizophrenia have been performed with the hope to identify novel, consistent and influential risk genetic factors. Finally, some schizophrenia susceptibility genes have been identified and reported in recent years and their biological functions are also listed. This review may serve as a summary of past research on schizophrenia genomics and susceptibility genes (NRG1, DISC1, RELN, BDNF, MSI2), which may point the way to future schizophrenia genetics research. In addition, depending on the above discovery of susceptibility genes and their exact function, the development and application of antipsychotic drugs will be promoted in the future.

miR­139­5p enhances cisplatin sensitivity in non­small cell lung cancer cells by inhibiting cell proliferation and promoting apoptosis via the targeting of Homeobox protein Hox­B2.

The development of chemotherapeutic dug resistance hinders the clinical treatment of cancer. MicroRNAs (miRNAs/miRs) have been revealed to serve essential roles in the drug resistance of numerous types of cancer. miR­139­5p was previously reported to be associated with cisplatin (DDP) sensitivity in human nasopharyngeal carcinoma cells and colorectal cancer cells. However, the effect and underlying mechanism of miR­139­5p in DDP sensitivity in non­small cell lung cancer (NSCLC) cells has not yet been fully elucidated. In the present study, the expression of miR­139­5p and Homeobox protein Hox­B2 (HOXB2) in NSCLC tissues was examined by reverse transcription­quantitative polymerase chain reaction (RT­qPCR) and western blotting. Subsequently, the effect of miR­139­5p on the DDP sensitivity of NSCLC cells in vitro was investigated. Cell proliferation was examined using a Cell Counting Kit­8 assay. Western blotting was used to evaluate the protein expression of HOXB2, phosphorylated (p)­PI3K, p­AKT, caspase­3 and cleaved­caspase­3, and RT­qPCR was used to evaluate the expression of miR­139­5p, and the mRNA expression levels of HOXB2, PI3K, AKT and caspase­3. The apoptotic rate of the cells was detected using flow cytometry. miR­139­5p expression in NSCLC tissues was shown to be significantly lower compared with that in adjacent tissues. Additionally, miR­139­5p increased cell apoptosis and inhibited NSCLC cell proliferation induced by DDP in vitro via modulating the PI3K/AKT/caspase­3 signaling pathway. Furthermore, HOXB2 was identified to be a target of miR­139­5p, and miR­139­5p was revealed to sensitize NSCLC cells to DDP via the targeting of HOXB2. Taken together, the results of the present study demonstrated that regulating the expression of miR­139­5p could provide a novel approach to reverse DDP resistance and increase chemosensitivity in the treatment of NSCLC.

Two-dimensional correlation spectroscopic studies on coordination between organic ligands and Ni2+ ions.

3A2g→3T1g(P) transition band of Ni2+ is used to probe the coordination of Ni2+. Two-dimensional asynchronous spectra (2DCOS) are generated using the Double Asynchronous Orthogonal Sample Design (DAOSD), Asynchronous Spectrum with Auxiliary Peaks (ASAP) and Two-Trace Two-Dimensional (2T2D) approaches. Cross peaks relevant to the 3A2g→3T1g(P) transition band of Ni2+ are utilized to probe coordination between Ni2+ and various ligands. We studied the spectral behavior of the 3A2g→3T1g(P) transition band when Ni2+ is coordinated with ethylenediaminetetraacetic acid disodium salt (EDTA). The pattern of cross peaks in 2D asynchronous spectrum demonstrates that coordination brings about significant blue shift of the band. In addition, the absorptivity of the band increases remarkably. The interaction between Ni2+ and galactitol is also investigated. Although no clearly observable change is found on the 3A2g→3T1g(P) transition band when galactitol is introduced, the appearance of cross peak in 2D asynchronous spectrum demonstrates that coordination indeed occurs between Ni2+ and galactitol. Furthermore, the pattern of cross peak indicates that peak position, bandwidth and absorptivity of the 3A2g→3T1g(P) transition band of Ni(galactitol)x2+ is considerably different from those of Ni(H2O)62+. Thus, 2DCOS is helpful to reveal subtle spectral variation, which might be helpful in shedding light on the physical-chemical nature of coordination.

MicroRNA-27a Promotes Inefficient Lysosomal Clearance in the Hippocampi of Rats Following Chronic Brain Hypoperfusion.

Chronic brain hypoperfusion (CBH) induces the accumulation of abnormal cellular proteins, accompanied by cognitive decline, and the autophagic-lysosomal system is abnormal in dementia. Whether CBH accounts for autophagic-lysosomal neuropathology remains unknown. Here, we show that CBH significantly increased the number of autophagic vacuoles (AVs) with high LC3-II levels, but decreased SQSTM1 and cathepsin D levels in the hippocampi of rats following bilateral common carotid artery occlusion (2VO) for 2 weeks. Further studies showed that microRNA-27a (Mir27a) was upregulated at 2 weeks compared with the sham group. Additionally, LAMP-2 proteins were downregulated by Mir27a overexpression, upregulated by Mir27a inhibition, and unchanged by binding-site mutations or miR-masks, indicating that lamp-2 is the target of Mir27a. Knockdown of endogenous Mir27a prevented the reduction of LAMP-2 protein expression as well as the accumulation of AVs in the hippocampi of 2VO rats. Overexpression of Mir27a induced, while the knockdown of Mir27a reduced, the accumulation of AVs and the LC3-II level in cultured neonatal rat neurons. The results revealed that CBH in rats at 2 weeks could induce inefficient lysosomal clearance, which is regulated by the Mir27a-mediated downregulation of LAMP-2 protein expression. These findings provide an insight into a novel molecular mechanism of autophagy at the miRNA level.

A flexible and superhydrophobic upconversion-luminescence membrane as an ultrasensitive fluorescence sensor for single droplet detection.

A Ln3+-doped (Yb3+, Tm3+ or Yb3+, Er3+ co-doped) NaYF4 nanoparticle/polystyrene hybrid fibrous membrane (HFM) was fabricated using an electrospinning technique. The HFM shows upconversion luminescence (UCL), flexibility, superhydrophobicity and processability. The UCL membrane can be used as a fluorescence sensor to detect bioinformation from a single water droplet (~10 µl). Based on the fluorescence resonance energy transfer, the detection limits of this sensor can reach 1 and 10 ppb for the biomolecule, avidin, and the dye molecule, Rhodamine B, respectively, which are superior to most of the fluorescence sensors reported in previous works. After the fluorescence detection, the target droplet was easily removed without residues on the UCL membrane surface due to its superhydrophobic property, which exhibits an excellent recyclability that cannot be achieved by traditional liquid-based detection systems.

MicroRNA-9 induces defective trafficking of Nav1.1 and Nav1.2 by targeting Navß2 protein coding region in rat with chronic brain hypoperfusion.

BACKGROUND: Previous studies have demonstrated that the trafficking defects of Nav1.1/Nav1.2 are involved in the dementia pathophysiology. However, the detailed mechanisms are not fully understood. Moreover, whether the impaired miRNAs regulation linked to dementia is a key player in sodium channel trafficking disturbance remains unclear. The cognitive impairment induced by chronic cerebral ischemia through chronic brain hypoperfusion (CBH) is likely reason to precede dementia. Therefore, our goal in the present study was to examine the role of microRNA-9 (miR-9) in regulating Nav1.1/Nav1.2 trafficking under CBH generated by bilateral common carotid artery occlusion (2VO). RESULTS: The impairment of Nav1.1/Nav1.2 trafficking and decreased expression of Navß2 were found in the hippocampi and cortices of rats following CBH generated by bilateral 2VO. MiR-9 was increased in both the hippocampi and cortices of rats following CBH by qRT-PCR. Intriguingly, miR-9 suppressed, while AMO-miR-9 enhanced, the trafficking of Nav1.1/Nav1.2 from cytoplasm to cell membrane. Further study showed that overexpression of miR-9 inhibited the Navß2 expression by targeting on its coding sequence (CDS) domain by dual luciferase assay. However, binding-site mutation or miR-masks failed to influence Navß2 expression as well as Nav1.1/Nav1.2 trafficking process, indicating that Navß2 is a potential target for miR-9. Lentivirus-mediated miR-9 overexpression also inhibited Navß2 expression and elicited translocation deficits to cell membrane of Nav1.1/Nav1.2 in rats, whereas injection of lentivirus-mediated miR-9 knockdown could reverse the impaired trafficking of Nav1.1/Nav1.2 triggered by 2VO. CONCLUSIONS: We conclude that miR-9 may play a key role in regulating the process of Nav1.1/Nav1.2 trafficking via targeting on Navß2 protein in 2VO rats at post-transcriptional level, and inhibition of miR-9 may be a potentially valuable approach to prevent Nav1.1/Nav1.2 trafficking disturbance induced by CBH.

Activation of Cdk5/p25 and tau phosphorylation following chronic brain hypoperfusion in rats involves microRNA-195 down-regulation.

Chronic brain hypoperfusion (CBH) is a common clinical feature of Alzheimer's disease and vascular dementia, but the underlying molecular mechanism is unclear. Our previous study reported that the down-regulation of microRNA-195 (miR-195) promotes amyloidogenesis via regulation of amyloid precursor protein and ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) expression at the post-transcriptional level in CBH rats with bilateral common carotid artery occlusion (2VO). CBH owing to unilateral common carotid artery occlusion (UCCAO) increases tau phosphorylation levels at multiple phosphorylation sites in the brain, but the molecular mechanism is poorly understood. The purpose of this study was to investigate whether miR-195 could both deregulate amyloid metabolism and indirectly deregulate tau phosphorylation in CBH. We observed that 2VO leads to tau hyperphosphorylation at Ser202/Thr205, Ser262, Thr231, and Ser422 and to the conversion from cyclin-dependent kinase 5 (Cdk5)/p35 to Cdk5/p25 in rat hippocampi. Endogenous miR-195 was knocked down using over-expression of its antisense molecule (pre-AMO-miR-195) via a lentivirus (lenti-pre-AMO-miR-195); this knockdown increased the tau phosphorylation at Ser202/Thr205, Ser262, Thr231, Ser422, and the Cdk5/p25 activation, but over-expression of miR-195 using lenti-pre-miR-195 decreased the tau phosphorylation and Cdk5/p25 activation. Further in vitro studies demonstrated that miR-195 over-expression prevented tau hyperphosphorylation and Cdk5/p35 activity, which were increased by miR-195 inhibition. A dual luciferase reporter assay showed that miR-195 bound to the Cdk5r1 gene, which encodes p35 protein, in the 3'UTR and inhibited p35 expression. We concluded that tau hyperphosphorylation involves the down-regulation of miR-195, which is mediated by Cdk5/p25 activation in 2VO rats. Our findings demonstrated that down-regulation of miR-195 led to increased vulnerability via the regulation of multiple targets. Schematic diagram of miR-195 mediated Aß aggregation and tau hyperphosphorylation in chronic brain hypoperfusion (CBH). First, CBH results in the elevation of nuclear factor-κB (NF-κB), which binds with the promoter sequences of miR-195 and negatively regulates the expression of miR-195. Second, down-regulated miR-195 induces up-regulation of APP and BACE1 and leads to an increase in Aß levels. Third, some of the elevated Aß then enter the intracellular space and activate calpain, which promotes the conversion of Cdk5/p35 to Cdk5/p25 and catalyzes the degradation of IκB; IκB is an inhibitor of NF-κB, which activates NF-κB. Cdk5/p25 directly phosphorylates Tau. Fourth, down-regulated miR-195 induces an up-regulation of p35, which provides the active substrates of p25. Our findings demonstrated that the down-regulation of miR-195 plays a key role in the increased vulnerability to dementia via the regulation of multiple targets following CBH.

Expression of amyloid-associated miRNAs in both the forebrain cortex and hippocampus of middle-aged rat.

BACKGROUND: Aging is associated with the gradual cognitive decline and shows the typical senile plaque formation in the brain, which results from the aggregation of beta amyloid (Aß) peptide following the abnormal proteolytic processing of amyloid precursor protein (APP) by ß-secretase (BACE1) and γ-secretase. Accumulating evidence indicates that several microRNAs (miRNAs) are involved in the Alzheimer's disease (AD) by regulating the expression of APP and BACE1 proteins. However, the cognitive ability and the expression profile of the APP- and BACE1-associated miRNAs in the middle-aged population are largely unknown. METHODS: The learning and memory ability in rats were determined by Morris Water Maze test. The protein levels of APP and BACE1 were detected by western blotting. The quantitative polymerase chain reaction was used to identify the miRNAs levels in forebrain cortex and the hippocampus. RESULTS: Middle-aged rats have declined learning ability without changes in the memory ability, and increased APP and BACE1 protein expression in the forebrain cortex. Computational analysis using Targetscan and Pictar databases reveals that totally 4 predicted miRNAs have conserved binding site with APP, namely miR-106b, -17-5p, -153, -101. All of them showed decreased expression in both the forebrain cortex and hippocampus. Among the 10 predicted miRNAs targeting BACE1, different expression profiles were identified in the forebrain cortex (decreased: miR-9, -19a, -135a, -15b, -16, -195, -29c, -214; increased: miR-124; no change: miR-141) and the hippocampus (decreased: miR-9, -15b, -16, -195, -29c, -124; increased: miR-19a, -135a, -214, -141) in the middle-aged rats compared with the young rats. CONCLUSION: Our results provided the first evidence that middle-aged rats have begun displaying cognitive disability with abnormal expression of APP- and BACE1-related miRNAs in the hippocampus and forebrain cortex.

MicroRNA-195 protects against dementia induced by chronic brain hypoperfusion via its anti-amyloidogenic effect in rats.

Previous studies have demonstrated that chronic brain hypoperfusion (CBH) causes Aß aggregation by upregulating expression of amyloid precursor protein (APP) and ß-site APP cleaving enzyme 1 (BACE1) protein, which is accompanied by cognitive impairment, but the mechanisms are not fully understood. In this study, we evaluated the effect of microRNA on memory impairment in rats induced by CBH. We show here that CBH generated by bilateral common carotid artery occlusion (2VO) significantly decreased the learning and memory ability in rats, as assessed by Morris water maze, and upregulated expression of APP and BACE1 proteins in the hippocampus and cortex of rats, as evaluated by Western blot and immunofluorescence. In reciprocal, qRT-PCR analysis showed that microRNA-195 (miR-195) was downregulated in both the hippocampus and cortex of rats following CBH, and in the plasma of dementia patients. APP and BACE1 proteins were downregulated by miR-195 overexpression, upregulated by miR-195 inhibition, and unchanged by binding-site mutation or miR-masks, indicating that APP and BACE1 are two potential targets for miR-195. Knockdown of endogenous miR-195 by lentiviral vector-mediated overexpression of its antisense molecule (lenti-pre-AMO-miR-195) elicited dementia in rats, whereas overexpression of miR-195 using lenti-pre-miR-195 reduced dementia vulnerability triggered by 2VO. Additionally, chromatin immunoprecipitation analysis showed that NFκB was bound to the promoter region of miR-195 and inhibited its expression. We conclude that miR-195 may play a key role in determining dementia susceptibility in 2VO rats by regulating APP and BACE1 expression at the post-transcriptional level, and exogenous complement of miR-195 may be a potentially valuable anti-dementia approach.